What do people do with Breather Outputs With No Airbox?

xsjohn

Ebay probably has tons of the airboxes cheap .....with as many people that chose to take them off........and the later plastic ones can be made to work good with a simple mod to add another inlet......like to make my own elements......not dusty here where I'm at all so they don't have to be restrictive......no noise.....no rain problem and no stink......and no expense....

xsjohn

jdallen

Jake68, how about this from a Norton site...."I use a one way breather flapper valve from a 1980s BMW Boxer breather system on my Dommie". This guy also lives in the UK.

5twins, thanks for the tip on the tube length. Now that I think about it I'm sure you're right.

metalredneck · Full Member Joined: Aug 04, 2008 Posts: 308

I put the check-valves in, ran the ass off the bike for the summer, and it is tighter than a banker's ass.

jdallen

well, you guys've got me sold. My check valves will be at the local store tomorrow.

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

Yeah dude...I saw that too...I went to my local BMW dealer and nearly fell over when he told me how much they cost!..But he did tell me I could get something similar from ex-British Leyland engine..which turned out to be another two hours wasted.

The simple fact is that the valves I could find to buy in the UK from pretty much anywhere..are too restrictive and screwed my gaskets and seals after 200 miles or so...I tried two different kinds of brake servo valves.

However the valve from Mikes is the architypal flapper valve we all need. It opens with the slightest pressure and does the job with ease.

Easiest just to get one of these, then mess with alternatives that may or may not work. Just go straight to the one designed to do the job.

John...oh I wish...I've had an eye out...but it aint that simple when you ripped out and customized all the electric system too...the one thing that works better by the way..

xsjohn

Drawing the crankcase vent back into the engine like the factory designed it is where it's at....if not something else is wrong...or a PO has dicked something somewhere like the restrictors or opened the vent somehow...you guys are putting yourself through a lot of hassels for nothing......except for the lovely view of a filter.....I walk pass that department.........ugly things they are......like chlamydia or something....

xsjohn

jdallen

There's always a way to improve something.......

It seems like these valves are only fairly recently being used by xs650 owners, but I found articles about this from Norton guys dating back to 2001. www.nortonclub.com/doc...rValve.pdf

I think there's a lot to be said for keeping these bikes restored original, but I also like what people are doing with them. Upgrading the xs650 isn't a new thing. I'm too young to remember this, but I've read about Kenny roberts and others, and I guarantee they weren't running it stock....

y one question is this.....if there is something wrong with the valve I install, how would I know it? Are there any signs or sounds I should listen for? Would the bike run differently, etc......

xsjohn · Last edited by xsjohn on December 2, 2008, 12:52 pm; edited 3 times in total

When these things make funny sounds the are telling us something....

xsjohn

jdallen

jake68, You mean like Mikes' rotor,.... or his old air pods....or the brake lever clamp of mine that just snapped like it was made of ceramic? I'm just joking a bit......actually I read those valves he sells sounds like a kazoo. Actually that might work......I can imagine it now.....the engine buzzing, the valves tapping, set mix screws lean for some popping on deceleration for rhythm and the breather valve whistling. Everybody would know I'm coming! Smile

xsjohn · Last edited by xsjohn on December 2, 2008, 12:54 pm; edited 1 time in total

Wonder what one of those valves would do witha stock air box.....

xsjohn

jdallen

John, I googled that and I found that "All of your PODs belong to Apple."

No seriously, I see what you're saying. some of these guys with the Brit bikes that led us to this magical brake valve may not be riding their bikes that much. Who knows. this is my commuter bike. It's only got 20K on it, and I've put 3k of those on in the last few months. complete top end rebuild...very little blow-by (but some) and a little seepage from a couple of places. the question remains, Is this check valve a good thing to do for the long haul? Who knows? But 5twins, tomterrific and others have been riding the hell outta their bikes with the valves and like the results......And don't forget metalredneck....you and I are both from North Carolina, so we've both grown up around some rednecks who like slayer and pantera and they may be some wild and crazy guys who really like whiskey....but they won't bullshit ya.

xsjohn

Yea.......red like the back of my neck.........

xsjohn

TeeCat

My '73 originally vented to atmosphere. I still run the stock hoses, but now each has a Motormite brake check vent on it, with a mini-pod on the end of each one. I can't really tell yet if I'm mitigating the bit of drooling that I suspect (after a main output and crank seal replacement) was/is coming from a small breach between the case halves because I'm "shunting" any oil in the bottom of the left case cover through a hose to one of the breather pods. But at the moment, there are no drips under the bike and the frame and sidestand seem to be quite clean. Not sure what else to do outside of that, really, but I see I'm not alone in my attempts to manage a bit of oil weeping.

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

John is f-ing right guys...taking your airbox off is a waste of time and ruins the intergrity of the bike. The extra power is minimal..you get a bad smell..and leaking gaskets...or at least a bad smell...

If hadnt trashed my box and one off'd the electrics I'll do something about it..

However without an airbox smooth opening low pressure one way valves are the only working real solution...you need to be able to open the valves very easily with just pressure from flexing your cheaks...never mind even blowing..any more resistance than that and it wont open..

TeeCat

Jake, question:

What would cause or contribute to positive CC pressure on an early bike with hoses vented to atmosphere from stock?

From Mike's valve product description:

Quote::

and the crankcase vacuum helps prevent crankcase
pressure from pushing oil past oil seals and case joints.

This may be/have been the case with my bike. I suppose time will tell, but I'm not sure what would contribute to case joint bleeding on a motor that, from stock, vents to atmosphere versus the airbox. Perhaps Yamaha hadn't discerned that yet! Rolling Eyes

I do run pods now, btw, but in the case of my early bike, I don't think the airboxes or lack thereof are a culprit.

In any case, I hope my vents are working and that they are reducing any positive pressure.

TC

xsjohn

Blow by would contribute to positive pressure......xsjohn

XS919

I made a catch can setup that sits in behind the carbs. I wanted something that would fill the hole left after I removed the original airbox and battery tray.

The catch can has 2 inputs at the top that connect to the breathers on the back of the head. There is a small K&N filter on top of the can that breathes to atmosphere. At the bottom of the can is a barb that has a line running to a fitting on the crank case. This lets oil collected in the catch can drain back into the sump.

I'll see if I can find a picture of it.

Cheers

ichael

TeeCat

Incidentally... how many of you lot actually run the little cork dipstick cover gasket? I don't... never knew there was one until recently... but I wonder if that might make it even easier for the breather valves to make some vacuum. I'd think that every little bit helps. Mike's has them, but that's a gasket that's easily made by oneself. I'll have to get/make one.

Also, when you add oil between changes, how much do you add at a time, and do you look for the "halfway between the marks" cold or hot? I would think cold, otherwise if you have residual oil up in the head, you risk overfilling. Rolling Eyes

yamaman

Cool, I didn't know there was supposed to be a gasket there TC. I have to crank the bejesus out of mine with multi-grips or it loosens and pushes oil out of it!
I get massive differences in my oil readings- even when I let it cool down, buggered if I know where it hides sometimes! I guess I'm lucky as I change oil most every time I ride it. Certainly though I fill it to just above the full mark.
Be good to know how far over full you can get away with.............any takers on that one? Though I realy should get a oil cooler first, I wouldn't mind a sump extension on mine:

www.xs650.org.au/Racers.htm

TeeCat

Quote::

Cool, I didn't know there was supposed to be a gasket there TC. I have to crank the bejesus out of mine with multi-grips or it loosens and pushes oil out of it!

Are you serious??!! Shocked

Mine never does that, and I just hand tighten mine! Wow! But I'm gonna fit a gasket as I suspect any little buttoning up of the crankcase can help those check valves. And it can't hurt! That's the second missing gasket I have discovered on my bike, the other being the little cork one that was supposed to be under the cam chain adjuster dome nut! And I'm wondering whether those two things combined could have contributed to my oil drooling.

Quote::

Be good to know how far over full you can get away with.............any takers on that one?

Well, on my early bike - a '73 TX - there was a service bulletin that was released regarding mismarked sticks leading to overfilling. I never knew it until 5twins told me I was overfilling by running 2.6 litres, per the manual! Shocked

Bless 5twins' cotton socks... that cat's pulled my fat out of the fire so many times! Rolling Eyes

Anyway, I go to halfway between the marks now (2 quarts), but I think that my bike has suffered the effects of overfilling by both the PO(s) and me, which may have contributed to my having to replace the output shaft and crank seals, and possible residual drooling from the case joint behind the alternator is something I'm still vigilant for. My in situ crank seal replacement seems to have been successful, though.

So yes! Worry about overfilling! And don't! Crying or Very sad

TC

yamaman

Yeah, but my poor best only gets started so it can have its neck rung, it doesn't get many easy runs! Laughing

Does yours have a steel or plastic dip-stick TC?

TeeCat

Oh, that's right... you do trackfests. I forgot.

I have a metal dipstick. But I shall fit a gasket after I get back from a little trip in the next week or so, and continue to watch closely for oil-related behavior.

I'm so glad I'm not alone in this. It seems not to be an indication of the need for a teardown... but a common trait!.

TC

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

TeeCat wrote:

Jake, question:

What would cause or contribute to positive CC pressure on an early bike with hoses vented to atmosphere from stock?

From Mike's valve product description:

Quote::

and the crankcase vacuum helps prevent crankcase
pressure from pushing oil past oil seals and case joints.

This may be/have been the case with my bike. I suppose time will tell, but I'm not sure what would contribute to case joint bleeding on a motor that, from stock, vents to atmosphere versus the airbox. Perhaps Yamaha hadn't discerned that yet! Rolling Eyes

I do run pods now, btw, but in the case of my early bike, I don't think the airboxes or lack thereof are a culprit.

In any case, I hope my vents are working and that they are reducing any positive pressure.

TC

Positive crankcase pressure can be caused by blow by piston rings bore clearence etc...thats what causes it when there is something wrong...

however...you WILL get positive pressure however slight in a well sorted motor if you remove your original airbox and fit pod filters.

After weeks of research and exchanging emails with a guy in Australia who is an expert on crankcase breathing in many different types of engine I learnt the issue...

We run a motor that has two pistons that arrive at the top both at once, causing no natural equalization of pressure. They are two quite large pots in a small space...taking off the induction breather system means that the original breather system now becomes a slight restriction...so just fitting a straight through breather system becomes say 50% effective in comparison to the inducted breather...

Natural blow by (which is unavoidable even in the most well sorted new engine) means that there is always more energy causing positive pressure than there is negative. Therefore with a straight through breather that has the same resistance to output as input you get positive pressure whether you like it or not.

The ONLY way round this is to fit the airbox back...OR..to fit very very freeflowing one way valves..

The airbox is smell free because its a sealed circuit...and lets say this is 100% effective as mostly it is...if thats try a well sorted one way valve setup is say 80% effective ...but it still smells.

I had a leak from my cam caps..(what I call them) and fitting the one way valve from Mikes which is easily opened...fixed it ..straight away..

Before that I had break servo valves that allowed too much positive pressure build before they opened..

ikes valve is a fast moving light flap of material ..

metalredneck · Full Member Joined: Aug 04, 2008 Posts: 308

Mine has a gasket, & works great. As far as adding oil, mine is a '74 TX when they changed the oil fill spec, but kept the old dipstick, so mI give her a tablespoon at a time until the level reaches the bottom line with the stick SCREWED IN like a Honda. Any more, & she spews like she caught a dose.

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Yamaha xs650